1. Field of the Invention
The present invention relates generally to external fixation systems used for securing separated or fractured segments of a bone in proper position, alignment, and orientation for healing or therapeutic manipulation.
2. Scope of the Prior Art
A wide variety of external fixation or wire tensioning systems are known to the orthopedic field. Two popular types are the "ring-and-rod" and the "jointed bar" systems, and several variations or hybrids based upon these two basic types are known. The "ring-and-rod" systems are characterized by longitudinal bars having pin-holding clamps which can be secured in different positions and angular configurations relative to the parts of a fractured bone requiring fixation. The longitudinal bars may optionally be mounted on one or more partial rings which circumscribe the bone. In contrast, the "jointed bar" systems are composed of several rigid segments coupled by various types of joints which may be locked in a desired configuration.
Jointed bar systems generally display the advantage of providing a greater range or degree of non-uniform articulation, but inherently present a significantly larger profile and greater complexity in positively securing the segments and joints in the desired configuration. Ring-and-rod systems may provide greater stability and a lower lateral profile with the ability to employ both screw fixation and wire tensioning, however their range of articulation is generally more limited and the available locations for positioning the screws and wire relative to the corresponding rods or rings may be insufficient (or less than desirable) for some applications.
Among systems utilizing rings, there is a further distinction between "through-the-ring" systems and "outrigger" systems. In through-the-ring systems, the main longitudinal rods, bars, and wire or pin holders extend through apertures in the ring itself and are secured in position by fasteners or clamps. In "outrigger" systems, the rods are connected to the rings by clamps which ride along the peripheral edge or rim of the ring. The outrigger systems can provide continuous adjustability in the position of the rods along the rings, but lack the stability and usually present a larger lateral profile than through-the-ring systems.
Several representative examples of commercially-available external fixation systems which exemplify the "ring and rod" and "jointed bar" systems and their hybrids or variations are disclosed in the papers accompanying this specification, and are incorporated herein by reference as though fully set forth and described in detail, along with the additional patents and prior art references made of record.